And two, SLI and multi-GPU support is added for COD:MW2. (From the release highlights)

Adds SLI and multi-GPU support for many top new gaming titles including Borderlands, Call of Duty: Modern Warfare 2, FIFA Soccer 10, and more.

If you are upgrading your drivers as always I recommend using Add/Remove Programs (or Programs and Features or Programs for Windows Vista and Windows 7) to do the actual uninstall of the current drivers, a reboot of the system, then a cleaning using Driver Sweeper, then another reboot of the system and then finally the installation of the current drivers. This ensures you get a clean installation of the new drivers and there aren’t any parts left behind to muck things up.